Distributed deflection structure employing dielectric support

ABSTRACT

A deflection structure for an electronic scanning device or the like such as a CRT wherein the improvement consists of dielectrically supporting within such device a deflection means such as helical or meander conductors disposed adjacent to the principle electron beam of such device.

United States Patent [1 1 Piazza et al.

[ 1 Nov. 19, 1974 [54] DISTRIBUTED DEFLECTION STRUCTURE 3,654,509 4/1972 Scott et a1 315/35 EMPLOYING DIELECTRIC SUPPORT 3,670,196 6/1972 Smith 315/35 3,689,852 9/1972 Epsztein et al. 315/35 Inventors: Richard Elliot Flam; Bozidar 3,705,327 12/1972 Scott 315/35 Janko, both of Portland, Oreg. 3,736,534 5/1973 Chaffee 315/35 [73] Assignee: Tektronix, lnc., Beaverton, Oreg. P W L rimary Examiner-James awrence [22] July 1973 Assistant Examiner Saxfield Chatmon, Jr. [21 l Appl. No.: 380,627 Attorney, Agent, or Firm-Adrian J. La Rue [52] US. Cl 315/3, 315/35, 315/36 [57] ABSTRACT 2137 5 g g A deflection structure for an electronic scanning device or the like such as a CRT wherein the improvement consists of dielectrically supporting within such [56] References cued device a deflection means such as helical or meander UNITED STATES PATENTS conductors disposed adjacent to the principle electron 3,376,464 4/1968 Loty et all 315/3 beam of such device. 3,504,222 3/1970 Fukushima.... 315/3 3,610,999 10/1971 Falce 315/35 10 Claims, 5 Drawing Figures 24 25 2 20 1 "111111 I 'i'lf' [f vlt'fi' l "1[ I I l 1 I I PATEmmavismq 849,695

2 END 3 VIEW SHEET 10F 2 MMIA BACKGROUND OF THE INVENTION Electronic scanning devices or the like usually employ delay line structures having a plurality of circuit elements as is well-known. Such deflection structures are used to deflect the principle electron beam rather than bunch the principle electron beam as in traveling wave tubes. The utilization of such structures requires support means. Heretofore, such support means have included metal pins, tabs, or rods having axis parallel to the beam axis. Such support means renders the structures less attractive at high frequencies due to the production of strong localized variations of deflection structure impedance in the vicinity of the support, by increasing forward coupling of the deflecting signal down the deflection structure via the increased intercapacitance, and in general by radiation from the metal supports which tend to become antenna at frequencies approximately 1 GI-I or greater. To overcome the disadvantage associated with metal or tab support members, one method is to make the support members sufficiently small in comparison to the deflection structure. This however, presents mechanical limitations in the manufacturing process. Another method supports the deflection structure by using supports which are pretuned during manufacture to provide a constant impedance of the deflection structure over a certain band of frequencies. This method however, will not allow operation over a wide band of frequencies and can suffer further due to limitations in manufacturing processes.

Dielectric support means have also been used in the prior art. One such method as disclosed in US. Pat. No. 2,828,440 employes a conventional elongated metal helix structure supported by means of longitudinal extending dielectric rods disposed around the helix. However, this method is to limit the bandwidth of such traveling wave tube by using the dielectric support members as a factor in limiting such bandwidth. A second method using a dielectric support, but for a traveling wave tube, structure is disclosed in US. Pat. No. 3,551,729. In this patent, a helix is supported by a plu' rality of dielectric supports parallel to the helix axis and contacting the helix. Such method is limited in that only parallel support means may be employed and is not a deflection structure.

Other types of support means are disclosed in US. Pat. Nos. 3,504,222, 3,527,976, and 3,670,l96. However, each has a similarity to the above discussed US. Patents and will therefore not be discussed.

SUMMARY OF INVENTION Deflection structures having support means made of a dielectric material reduce to a minimum most of the disadvantages of the prior art as mentioned above as they will not produce strong localized variations in impedance, increased forward coupling significantly down the structure, nor will they radiate to any appreciable extent. These factors tend to extend considerably the bandpass of the deflection structures over conventional mounting techniques.

It is therefore an object of the present invention to provide an improved method of employment of dielectric supports for electronic scanning devices electron beam deflection structures.

It is yet another object of the present invention to provide dielectric support means containing a plurality of such supports.

It is still yet another object of the present invention to provide an improved deflection structure for an electronic display device having dielectric support members.

It is a further object of the present invention to provide an improved deflection structure for an electronic display device at minimum cost.

These and other objects of the present invention will be apparent to those skilled in the art from the following detailed description of the invention taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS In the drawings:

FIG. 1 is a solid comb of dielectric support means;

FIG. 2 is a separate dielectric support means secured to glass rods to support such means;

FIG. 3 is solid dielectric support means;

FIG. 4 is a dielectric support means using various combinations shown in FIG. 1-3; and

FIG. 5 is a deflection system according to the present invention.

DESCRIPTION OF INVENTION Referring to the drawings, and in particular to FIG. 1, a solid comb of dielectric support means 1 is provided. Supports 2 are made of a dielectric material and are a portion of the solid comb. A deflection structure 3, which may be helical as shown in FIG. 1 or meander, is bonded to the deflection structure via anyone of several techniques known such as brazing, epoxy or other suitable cement", and by an electroplating operation. It should be noted that the above mounting technique is not restricted to externally supported structures, i.e., the dielectric supports may be attached to the inside of a helical deflection structure as will be explained later in the description. As the dielectric supports have a reasonably low dielectric constant, they will not produce strong localized variations in impedance, increase forward coupling significantly down the structure, nor will they radiate to any appreciable extent. Another feature of the present invention and which can be discerned from the drawing of FIG. I is the flexibility in geometry of external ground plane 4 placed on the back side of the helix 3 so that an electron beam 5 is between such helix and ground plane.

FIG. 2 shows another embodiment of the present invention. Dielectric supports 6 are embedded into glass rod 7 at one end and bonded to a deflection structure 8 at the opposite end as described above. Here again, the electron beam 9 is deflected between ground plane 10 and the deflection structure 8. Such construction enables deflection structure 8 to be supported as desired i.e., it is not necessary to connect each turn of the deflection structure to a separate dielectric support.

Another method of supporting a deflection structure is shown in FIG. 3. A solid block or bar of dielectric material 11 has a deflection structure 12 bonded to such dielectric support. As in the previous two drawings, an electron beam 13 is deflected between the deflection structure 12 and a ground plane 14.

FIG. 4 shows various methods already described along with FIGS. 1-3 for providing a deflection structure according to the present invention. Using these techniques of construction, single ended or balanced deflection structures are possible. In each end view shown, the dielectric supports have been given the reference number while the deflection structure, electron beam, and ground plane(s) are identified as l6, l7, and 18 respectively.

Shown in FIG. 5 is a complete deflection structure according to the present invention. Basically, two helical delay lines having flat surfaces are assembled into a balanced deflection system using the above listed techniques. The deflecting field appears in the gap between the helices which are contoured to provide the required sensitivity and scan. The impedance of such line can be set to match the deflection amplifier used with such structure.

Dielectric supports 19 are embedded into glass rods 20 and 21. The other end of such dielectric supports are bonded to the balanced and identical helical wound deflection structures 22 and 23. The deflection structure is then placed between deflector end supports 24 and 25. Such end supports may be bonded or secured to glass rods 20 and 21 using known methods and are provided with appropriate apertures for receiving and outputing the electron beam 26 as is wellknown.

As can further be seen in FIG. 5, each turn of helical members 22 and 23 is supported at a point 27 which is close to the electron beam path at the reverse side of the deflection structure facing the electron beam. As portions of the helix which provide the deflecting field are supported, mechanical precision of the active part of the deflector is insured. Thus, the active deflecting portions of the helix may be positioned so as to achieve distortionless deflection when, say the deflection structure is used in a high quality CRT. It should be noted that if the configuration of the helical conductor is insufficient to shield the dielectric support from the electron beam adequately, the support can be made slightly conductive to bleed away spurious charges.

While there has been shown and described the preferred embodiments of the present invention, it will be apparent to those skilled in the art that many changes and modifications may be made without departing therefrom in its broader aspects. For example, the helix need not have flat surfaces but such surfaces are usually associated with deflection structures used for deflection of an electron beam. Therefore, the appended claims are intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.

The invention is claimed in accordance with the following:

1. Dielectric supported deflection means comprising:

an array of non-conductive mutually parallel members having one end a solid body and the other end forming a comb structure having teeth extending therefrom; and

an array of conductive members defining helical deflection means bonded to the teeth of the nonconductive parallel members, said helical deflection means defining helix members having flat surfaces.

2. Dielectric supported deflection means comprising:

an elongated non-conductive member defining a glass rod; an array of non-conductive parallel members having one end supported within said elongated member 5 and the other end forming a comb structure having teeth extending therefrom; and

an array of conductive members defining helical deflection means bonded to the teeth of the nonconductive parallel members, said helical deflection means defining helix members having flat surfaces.

3. An electronic scanning device deflection structure having dielectric supports, comprising:

elongated mutually parallel non-conductive members defining glass;

a plurality of arrays of non-conductive mutually parallel members defining ceramic having one end secured to the elongated members;

a plurality of helical deflector conductive members defining helix members having flat surfaces bonded to said array of parallel non-conductive members; and

support means for supporting said elongated members in the scanning device.

4. The helix members according to claim 3 wherein said flat surface of one such member faces the flat surface of the other such member.

5. The structure according to claim 3 wherein said parallel non-conductive members position said plurality of arrays of conductive members so that distortionless deflection occurs.

6. The structure according to claim 3 wherein said support means defines metal further including apertures for receiving and outputing an electron beam respectively.

7. The support means according to claim 6 wherein said aperture for receiving said electron beam defines a circular opening in said metal.

8. The support means according to claim 6 wherein said aperture for outputing said electron beam defines an elongated circular opening in said metal.

9. An electronic scanning device comprising:

an evacuated envelope;

an electron gun, including an electron emissive cathode, positioned in one end of said evacuated enve lope for projecting a beam of electrons;

electron collecting means defining a cathode-raytube target positioned at the opposite end of said evacuated envelope from said electron gun; and

deflection means positioned between said electron gun and said electron collecting means, said deflection means including two mutual facing helical conductors defining helix members having flat surfaces supported within said envelope by dielectric support means for precisely positioning said helical conductors adjacent said projected electron beam.

rigid alignment within said evacuated envelope. 

1. Dielectric supported deflection means comprising: an array of non-conductive mutually parallel members having one end a solid body and the other end forming a comb structure having teeth extending therefrom; and an array of conductive members defining helical deflection means bonded to the teeth of the non-conductive parallel members, said helical deflection means defining helix members having flat surfaces.
 2. Dielectric supported deflection means comprising: an elongated non-conductive member defining a glass rod; an array of non-conductive parallel members having one end supported within said elongated member and the other end forming a comb structure having teeth extending therefrom; and an array of conductive members defining helical deflection means bonded to the teeth of the non-conductive parallel members, said helical deflection means defining helix members having flat surfaces.
 3. An electronic scanning device deflection structure having dielectric supports, comprising: elongated mutually parallel non-conductive members defining glass; a plurality of arrays of non-conductive mutually parallel members defining ceramic having one end secured to the elongated members; a plurality of helical deflector conductive members defining helix members having flat surfaces bonded to said array of parallel non-conductive members; and support means for supporting said elongated members in the scanning device.
 4. The helix members according to claim 3 wherein said flat surface of one such member faces the flat surface of the other such member.
 5. The structure according to claim 3 wherein said parallel non-conductive members position said plurality of arrays of conductive members so that distortionless deflection occurs.
 6. The sTructure according to claim 3 wherein said support means defines metal further including apertures for receiving and outputing an electron beam respectively.
 7. The support means according to claim 6 wherein said aperture for receiving said electron beam defines a circular opening in said metal.
 8. The support means according to claim 6 wherein said aperture for outputing said electron beam defines an elongated circular opening in said metal.
 9. An electronic scanning device comprising: an evacuated envelope; an electron gun, including an electron emissive cathode, positioned in one end of said evacuated envelope for projecting a beam of electrons; electron collecting means defining a cathode-ray-tube target positioned at the opposite end of said evacuated envelope from said electron gun; and deflection means positioned between said electron gun and said electron collecting means, said deflection means including two mutual facing helical conductors defining helix members having flat surfaces supported within said envelope by dielectric support means for precisely positioning said helical conductors adjacent said projected electron beam.
 10. The dielectric support means according to claim 9 further including a plurality of elongated mutually parallel non-conductive members, a plurality of arrays of non-conductive mutually parallel members having one end secured to and along said elongated parallel members, and the other end secured to said helix members, and next support means for supporting said elongated mutually parallel non-conductive members in rigid alignment within said evacuated envelope. 